Stopper rod and cassette using the same

ABSTRACT

This invention relates to a cassette ( 1 ) for supporting substrates and includes a pair of frames ( 2 ) opposite each other, at least two supporting bodies ( 3 ) arranged opposite each other between the frames, and at least a stopper rod ( 4 ) arranged between the frames. The frames, the supporting bodies and the stopper rods define a space for accommodating the substrates, and each stopper rod includes a metal rod ( 40 ) and a resin layer ( 42 ). The resin layer forms a coating on the metal rod, forming a unit.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a stopper rod and a cassette using the same, and more particularly to a stopper rod for use in the transport of substrates.

[0003] 2. Description of the Related Art

[0004] Cassettes are used to handle substrates, such as glass substrates for LCDs, for purposes of stowing, holding or cleaning substrates, to prevent the substrates from contacting one another. In general, the cassette has a box-shaped space for holding the substrates and the box-shaped space is formed by a pair of frames, several pairs of columns or planar supports defining grooves across the sides thereof, and several stopper rods for keeping substrates in the cassette. The substrates are accommodated between opposite supporting columns or planar supports, opposite edges of the substrates fitting in grooves in the sides of the columns or planar supports. TO clean the surfaces of the substrates, a plurality of substrates accommodated in a cassette are first put into a chemical solution pool and are then put into a pure water pool remove chemical solution residue.

[0005] The stopper rod of the conventional cassette described comprises a metal rod and a resin-made sleeve, and the metal rod is located in a through hole defined in the resin-made sleeve. The metal rod of the stopper rod makes the stopper rod strong enough and the resin-made sleeve has a soft surface to protect the substrates from harm.

[0006] If a diameter of the through hole of the resin-made sleeve is smaller than the diameter of the metal rod, assembly of the stopper rod is difficult; if the diameter of the through hole of the resin-made sleeve is larger than the diameter of the metal rod, a space may be formed between the metal rod and the resin-made sleeve. During cleaning, chemical solution entering the space may not be completely removed and subsequent production steps may be impaired by contamination by the residue chemical solution.

[0007] For the above reasons, an improved stopper rod which is easy to wash is desired.

SUMMARY OF THE INVENTION

[0008] An object of the invention is to provide a stopper rod which is easily cleaned.

[0009] Another object of the invention is to provide a cassette using the stopper rod.

[0010] In order to achieve the objects set forth above, a cassette for supporting substrates comprises a pair of frames opposing each other, at least two supporting bodies arranged opposite each other and fixed between the frames, and at least a stopper rod arranged between the frames. The frames, the supporting bodies and the at least stopper rod define a space for accommodating substrates. Each stopper rod comprises a metal rod and a resin layer. The resin layer coats the metal rod, forming a unit.

[0011] A plurality of substrates are mounted in the space in the cassette and are cleaned in a chemical solution while mounted in the cassette. After cleaning, chemical solution remains on the outer surfaces of the resin layer, the frames and the supporting bodies after leaving the chemical solution pool, and may easily cleaned off with pure water. Furthermore, the resin layer coating the metal rod has enough thickness to act as a protecting layer, preventing the substrates from knocking against the metal rod.

[0012] Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the preferred embodiment of the invention as illustrated in the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view of a metal rod of a stopper rod according to the present invention;

[0014]FIG. 2 is a perspective view of the stopper rod of the present invention;

[0015]FIG. 3 is a perspective view of a cassette of a first embodiment employing stopper rods;

[0016]FIG. 4 is a perspective view of a cassette of a second embodiment employing stopper rods.

DETAILED DESCRIPTION OF THE INVENTION

[0017] Reference will be made to the drawings to describe the invention in detail.

[0018] Referring to FIG. 1 and FIG. 2, a stopper rod 4 of the present invention comprises a metal rod 40 and a resin layer 42. The resin layer 42 coats the metal rod 40, forming a unit. The stopper rod 4 defines a hole 401 in each of two opposite ends for coupling with frames to assemble a cassette for accommodating substrates.

[0019] The material of the resin layer 42 can be polytetrafluoroethylene (PTFE). The resin layer 42 can be made by two methods. First method is a surface coating method comprising the steps: putting the metal rod 40 in a sterile environment; heating resin until fused; spraying the fusion resin on the surface of the metal rod 40, thus forming a uniform resin layer 42 having at least a 500 micrometers thickness. A second method uses an injection molding and comprises the steps: putting the metal rod 40 into a mold cavity; heating the resin until fused; and injecting the fused resin into a space between the metal rod 40 and the inner surface of the mold cavity; opening the mold; and cooling the stopper rod 4.

[0020] The stopper rod 4 made using the recited methods, consisting of the metal rod 40 and the resin layer 42, forms a unit and prevents chemical solution from remaining on the metal rod 40 after the process of cleaning.

[0021] Referring to FIG. 3, a cassette 1 for accommodating substrates includes a pair of frames 2, and a plurality of supporting bodies 3 and two stopper rods 4 arranged oppositely between the frames. The supporting bodies 3 are plates which face each other. Each supporting body 3 defines a plurality of grooves (not labeled) on an inward facing side, the grooves being so positioned that a group of grooves in a same horizontal plane cooperate with each other to stow one substrate. The frames, the supporting bodies 3, and the stopper rods 4 define a space therebetween for accommodating substrates and leave an entrance for inserting the substrates into the space.

[0022] The substrates are cleaned in a chemical solution pool while they are stacked in the cassette. After cleaning, some chemical solution remains on the outer surfaces of the resin layer 42, the frames 2 and the supporting bodies 3 after the cassette 1 is removed from the chemical solution pool. Such residue chemical solution can be easily cleaned with pure water. Furthermore, the resin layer 42 coating the metal rods 40 has enough thickness to act as a protecting layer, preventing the substrates from knocking against the metal rods 40.

[0023] In use, the substrates (not shown) are inserted through the entrance and into the space in the cassette, each substrate sliding alone the grooves in a common plane and being stopped when they contacting the stopper rods 4. When the cassette is full, the entrance can be closed by more stopper rods 4 to prevent the substrates from falling out of the cassette.

[0024] Referring to FIG. 4, a cassette 1′ of another embodiment of the present invention is similar to the cassette of FIG. 3, except that the cassette 1′ of FIG. 4 has the supporting bodies 3′ which are shaped roughly cylindrically and having a plurality of parallel wing panels (not labeled).

[0025] It is to be understood, however, than even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and change may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

What is claimed is:
 1. A cassette for supporting substrates, comprising: a pair of frames opposite each other, at least two supporting bodies arranged opposite each other between the frames, and at least a stopper rod arranged between the frames, wherein the frames, the supporting bodies and the stopper rods define a space for accommodating substrates, and each stopper rod comprises a metal rod and a resin layer, and the resin layer coats the metal rod, forming a unit of the metal rod and resin layer.
 2. The cassette as described in claim 1, wherein a thickness of the resin layer is at least 500 micrometers.
 3. The cassette as described in claim 1, wherein the resin layer is made using a surface coating method.
 4. The cassette as described in claim 1, wherein the resin layer is made using an injection molding method.
 5. A stopper rod of a cassette for accommodating substrates, comprising: a metal rod, and a resin layer, wherein the resin layer coats the metal rod, forming a unit of the metal rod and resin layer.
 6. The stopper rod as described in claim 5, wherein a thickness of the resin layer is at least 500 micrometers.
 7. The stopper rod as described in claim 5, wherein the resin layer is made using a surface coating method.
 8. The stopper rod as described in claim 3, wherein the resin layer is made using an injection molding method.
 9. A cassette for supporting substrates, comprising: a pair of frames opposite each other, at least two supporting bodies arranged opposite each other between the frames to from restriction in a first horizontal direction, and at least a stopper rod disposed beside said supporting bodies to form restriction in a second horizontal direction perpendicular to said first horizontal direction; wherein each of said stopper rods comprises a metal rod and a resin layer, and the resin layer coaxially enclosing the metal rod, forming a unitary piece of the metal rod and resin layer without any gap therebetween so that water can not axially invade an interior of said resin layer and exterior of the metal rod. 